O.S. Engines Support Ask Bill Baxter your questions about O.S. Engines.

tuning v series OS 92 4 stroke

Reply
Old 01-24-2013, 05:04 PM
  #1
berge
Thread Starter
 
Join Date: Feb 2011
Location: brisbane, AUSTRALIA
Posts: 15
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default tuning v series OS 92 4 stroke



Could you please advise what could be causeing this problem,My os 92 4 strokestarts and runs very good except the revs drop at full open throttle . When I reduce throttle to about three quarter open the revs peak to about 9200 rpmand the motor runs smooth. The pick up from idel is good and range of revs is good up to three quarter throttle,but when stick is moved beyond this to full open the motor falters a little and peak revs drop. I have made minor alteration to bottom end without success. The needle setting is 2 turns out and running 14x7 apc prop. Looking forward to your reply. Thanking You Glenn

berge is offline  
Reply With Quote
Old 01-25-2013, 07:03 AM
  #2
Bax
Moderator
 
Join Date: Apr 2002
Location: Monticello, IL
Posts: 19,479
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: tuning v series OS 92 4 stroke

It sounds like the engine just isn't getting enough fuel. You may want to reset the carburetor. Start out with the idle mixture set much, much too rich. Set the high-speed needle at a very rich setting, 3 turns or so. Start the engine at part throttle and then open the throttle to full. Do not remove the glow plug battery yet.

Adjust the high-speed mixture until the engine is running at peak RPM. Then richen it slightly. If the engine will sustain running "all day" when leaned to just rich of peak RPM, then it's broken-in enough to idle. Retard the throttle and adjust the idle mixture as needed to keep it running well. Because you know the idle mixture was purposely set very rich, you know it will have to be leaned.

By working with the idle RPM and mixture, you can eventually find the proper setting for a good idle. Lower is better, but only if you have a good throttle transition. Any idle below 2,200-2,500 RPM is good.
Bax is offline  
Reply With Quote
Old 01-29-2013, 01:04 PM
  #3
berge
Thread Starter
 
Join Date: Feb 2011
Location: brisbane, AUSTRALIA
Posts: 15
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: tuning v series OS 92 4 stroke

Thank you for your responce
berge is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 04:01 PM.